1. Field of the Invention
The present invention relates to a receiving apparatus, a receiving method, a transmission system and a transmission method which communicate by transmitting multiplexed digital signals of varying types.
2. Description of the Related Art
In the conventional art, there is available an apparatus which employs analog communications, such as an analog-type mobile telephone, to transmit signals of two or more varieties, such as a voice signal and electrocardiogram data. The apparatus transmits each signal by dividing the transmission band, while the receiving side employs an analog filter or the like to sort out each signal.
However, the analog filter cannot completely separate each signal, so that it may occur that one signal is included in other signal. Additionally, the analog communication system is susceptible to noises which are included on the transmission line or transmission channel, so that it becomes difficult to provide steady communications. On the other hand, a digital communication system, such as a portable telephone, a land-based mobile radiotelephone (i.e., cellular system), or the like is able to transmit only one type of signal per channel. Therefore, in the case of the digital communication system, it is necessary to provide a mobile apparatus for each type of signals in the case where two or more signals are transmitted at the same time. Accordingly, this requires that a plurality of mobile apparatuses be operated simultaneously.